If the plugs don't physically fit, then you can hit the dealer for the plug ends that match the ecu, and repin the harness.

If you do a little research before buying the ecu, you should be able to find one that matches the plug ends you have though.

 

You can not do this with all auto harnesses. Some auto harnesses have plugs with larger pins that will not fit into manual plugs. I have 2 99 harnesses here one auto one manual and the auto pin physicaly will not fit into the manual plugs. Toyota I guess thought it was funny to change things up every year. I have found late 95-early 97 manual share the same plugs, late 97- to early 03 share the same plugs. However there may only be 5 plugs that plug into your ecu, but there are 8 differant plugs available. This just for the ecu, there are 3 differant body plugs. I have about 20 differant harnesses and its almost funny how differant they are.

 

Finally got the 3.4 in.

Some issues:

• 3.4 alternator seems to be hitting the steering shaft when you tension it.
• Still trying to get a wiring solution down.... TMZ left you a voicemail....
• Can I run a catch can for PCV from valvecovers, or does the air have to be put back into the intake due to the Mass Air Metering?

 

i needed to run a shorter belt cause i had the same problem with the alt, i tried doing the catch can thing but it ran like crap and threw a code, i hooked it up stock and runs fine. did you get the ewd i sent?

 

I did, TY!

 

x2 on the PCV. You want it hooked up like the stock configuration.

If your alternator bracket touches the steering shaft, or is really close, you need to cut off the L bend and loose the adjustment screw. With my 1" body lift I didn't have to do that. Without the adjustment screw it is harder to CORRECTLY tension the belt than you think and it turns into a two person job, one operating the crowbar and the other to tighten the locking screw. You will want to use a belt tension gauge (I have the OTC gauge) to make sure the tension is correct, because the deflection method (1/4", 1/2" etc...) is not even remotely accurate.

 

I removed the adjusting screw on mine and did the prybar/wrench method to get it good and tight. It's been 60 000 kms (40,000 miles) without a problem.

 

OK, few more issues guys:

How do you wire the alternator? The plug from the body harness in the truck does not match the 3.4 alternator. Do you take the 3.4 connector and splice it into the 3.0 body harness?

Oil pressure sender - same as above.

The firewall donut/seal on my 3.0 harness is damaged - can a new one be purchased to put on the 3.4 harness?

 

1. You can just splice the 3.4 lower battery harness into the old 3.0 body harness, which keeps it fused. Doesn't matter which alternator you choose to use, just different plug ends.

2. Remove the 3.4 sender, install the 3.0 sender. Solder on the connector, and hook it up to the 3.4 harness.

3. Yupp, you can buy them at the dealer.

 

OK, I was asking because the wires on the 3.0 alternator are a LOT bigger.

 

I used the 3.0 wiring harness for the alternator. Cut the plug off the end of the 3.4 harness, soldered it onto the old 3.0 harness, and voila.

Did you do the tach mod?

 

I will be.....

 

I did the same thing and had some concerns about the different gauge sizes of the wiring but I just cut the 3.4 plug off close to the end and twisted it a number of times around the heavier 3.0 wires before I soldiered it. The hard part was getting all the shrink tube over the wiring before hand. You could use tape I suppose but I'm too Adult ADD for that (Attention to Detail Disorder)

 

how did you guys deal with the a/c? my braket wont fit from the 92 truck to the 97 4runner block. It's not even close. if i use the 3.4 bracket i'm sure i'll run into the hose being too short. Any help would be awsome.

 

Swap the top plate on the compressor from the 3.0 to the compressor on the 3.4. My engines have the compressor mounted in the exact same spot on the block, so the hoses hook up exactly as they did with the 3.0.

 

You may have to customize the 3.4 AC bracket some to fit between the 3.0 motor mount bracket and the 3.4 block. Because the motor mount bracket is thicker on the 3.0 (cast part).

 

Trying to jumper the auto trans harness to fool the ECU into thinking its in Neutral - anyone have tip on what pins/wires need jumped?